focusing

Discussion in 'Darkroom Equipment' started by veke, Sep 4, 2013.

  1. veke

    veke Member

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    I have tried with a focus finder but with spectacles I found it quite desperate. I couldn´t find the grain or to get a view of the photo to know where I am pointing at. Some areas in the photo (like eyes in a portrait in the negative) are sharp but some areas are out of focus due to short depth of field (the blurry background). Should I point at some lighter areas or the darker areas, at the moment I don´t see what I am focusing on...all blackness. Or a very bright light from the enlarger, not good for eyes to stare at it.

    Perhaps something is wrong with the mirror of the finder, or I don´t know how to use it correctly. I corrected the lens for my eyesight (a sharp line in the middle). Is there any other way? These finders are pretty expensive, 80 euros, don´t want to buy a new one just to check if this old one is good, or damaged. Magnifying glass costs 2 euros, does someone use that?

    I guess this is "The Question of the Month!" I have some other questions in store just in case this doesn´t win any prize.
     
  2. BMbikerider

    BMbikerider Member

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    You don't make it clear what you are trying to focus. Is it a manual focus camera, or a grain focusing magnifyer used in the dark room when using an enlarger.

    If it is the latter, most grain focussing devices can be adjusted for defective eyesight so that may cure the problem. If it is a manual focus camera screen you are looking at, it may be possible to buy a correction lens to bring the screen into sharp focus. Some cameras actually had a focus adjuster for sight defects built in.

    It may help if you give us a better idea of what you are using to make sure we are talking about the same thing.
     
  3. Rudolf Karachun

    Rudolf Karachun Subscriber

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    As I understand, it is a grain focuser. When you just starting using a grain focuser, it is not that clear what to look for and where the grains are. It's getting better with experience. Don’t look for the image, you will not be seeing it. Concentrate just on the grains. Locate the grain focuser in the area of the image with maximum density, close the lens aperture a few stops, and try to look through the focuser on the separate grains. Move slightly the enlarger focusing mechanism, and you will see that the grains became more or less sharp in the focuser. And it is no difference how sharp the image by itself. The negative theoretically is the flat surface located parallel to the focusing board, that means that all grains are on the same distance to the focusing board, and all of them will be visible sharp when enlarger focused correctly even if the negative not sharp at all.
     
  4. AgX

    AgX Member

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    When enlarging you could use a substitute-film for focusing. There had been substitutes offered with special graphics (fine lines etc.) been exposed on a strip of 35mm film. After framing and roughly focusing your negative, it is substituted by that special one. At least when working with a two-glasses film cassette in your enlarger and orientating film and substitute the same way, that approach should facilitate critical focusing with difficult negatives.

    Last year or so we had a lenghty discussion here about adjusting a grain-focuser.
     
  5. jeffreyg

    jeffreyg Subscriber

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    Some grain focusers have to be focused. The one I have has an outlined rectangle and an adjustable eyepiece. I make sure that is sharp before using it (I believe you did that but check before each use). Have the focuser on a piece of the same weight paper you will be printing on in the easel. Unlike Rudolf, I focus wide open and then stop down assuming that if it is focused wide open it will be that much better stopped down but everyone has their own technique. I don't look through my reading glasses when using the grain focuser.

    http://www.jeffreyglasser.com/
     
  6. Rudolf Karachun

    Rudolf Karachun Subscriber

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    Yes, I focusing a wide open too. But for the first time user, if he don’t see the grains, to close the aperture a bit, can be helpful.
     
  7. MattKing

    MattKing Subscriber

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    A "focus finder" is used to check the enlarger's focus, not how well focused the original negative is.

    There are essentially two types - a lower magnification type that shows more of the image area, and a higher magnification type that shows more of the grain (aka a "grain focuser").

    I use both types, because my lower magnification Bestwell Magna Sight is better in the corners and much easier to use when the enlarger head is quite high, well my grain focuser is more definitive near the centre.

    In either case, they work best when there are both dark and light areas in the field of view. The Magna Sight is easier to use when the area in view is also sharply delineated in the negative.
     
  8. cliveh

    cliveh Subscriber

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    Try using it without spectacles.
     
  9. Hatchetman

    Hatchetman Subscriber

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    Try moving your eye way back from the lens and move it forward until the grain comes into focus (hopefully). you don't stick your eye right up to the grain focuser.
     
  10. veke

    veke Member

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    thanks!
    Yes, I explained poorly but the issue is focusing the negative on the paper when enlarging. And the "focus finder" comes from this ad. Not my advertisement but this is the device I tried to use. Now it is 105 euros. I just don´t use it properly, the correct way. I will keep on trying. There has been a previous topic but under grain focusing not focus finding. I will put now the ad and the previous topic as links.
    http://www.telefoto.fi/tuote/579/4129/paterson-major-focus-finder-raetarkennin-ptp644
    and the topic here earlier,
    http://www.apug.org/forums/forum43/59027-how-use-grain-focuser.html

    back to the drawing-board...
     
  11. John Koehrer

    John Koehrer Subscriber

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    The Patersons rely on your focusing on an aerial image. That's why you adjust for the line to be sharp.
    The grain isn't on a surface but is supposed to be seen at the same plane as the line.

    I've never been able to use one myself, I can't seem to wrap my mind(eyes) around how it works. I end up using the image on the base board & reading glasses. A large diameter magnifying glass might also work.
     
  12. pentaxuser

    pentaxuser Subscriber

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    Your link tells me that it is the Paterson Major Grain Focus Finder. I have both Minor and the Major and your are right about how to focus. It is the line across the middle that needs to be sharp. Get this sharp either with glasses or without then depending on whether you got the line sharp with or without glasses use it with or without glasses.

    I have used both of mine with and without glasses and they seem to work OK with or without glasses. I am puzzled as to why you cannot get the grain into focus. If the grain is in focus then the neg will be also in focus except in the situation mentioned below.

    Be aware that if the neg itself is out of focus then the grain will still come into focus but the print will be out of focus and never will be in focus. Nothing will make a fuzzy out-of-focus negative sharp.

    pentaxuser
     
  13. AgX

    AgX Member

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    "Be aware that if the [image on the] negative is out of focus then..."